Republic of the Philippines
SORSOGON STATE UNIVERSITY
College of Engineering and Architecture
Bibingcahan Baribag, Sorsogon City
Tel. No.: (056) 211 0178
General Geology: Geology in Civil Engineering
Section:
BS Civil Engineering 2B
Members:
Alcasid, Jelinrold
23174977
Baring, Ziphora Jane D.
23164917
Bon, Riza B.
22152419
Objectives:
The objective of this section is to provide a foundational understanding of the significance of
geology in civil engineering. It aims to define both geology and civil engineering, highlight the
relationship between the two disciplines, and explore the different branches of geology, the Earth's
structure and composition, and an introductory understanding of continental drift and plate tectonics.
By the end of this section, readers will gain an appreciation about the influence of geological factors in
engineering contexts.
Lesson 1: Introduction to Geology
Definition of Geology and Civil Engineering
Geology is the scientific study of the Earth, including its materials, structure, processes, and
history. It focuses on understanding the development of the Earth's physical structure, as well as the
processes that continue to shape it (e.g. erosion, sedimentation, and tectonic movements). Also, it
involves the study of minerals, rocks, soil, groundwater, and natural hazards like earthquakes and
landslides. (Libretexts, 2022).
Civil Engineering is a branch of engineering that specializes in the design, construction, and
maintenance of infrastructure projects such as roads, bridges, buildings, dams, and other public
works. Civil engineers work to ensure that these structures are functional, safe and sustainable in
terms of the environment and society.
Overview of Their Relationship
The relationship between geology and civil engineering is essential, as geological factors play
a significant role in the success or failure of civil engineering projects. Civil engineers must
understand geological principles to make informed decisions about the design, construction, and
maintenance of infrastructure. Geology provides critical information about the conditions of the land,
the availability and stability of materials, and the behavior of the ground under different conditions. In
turn, this geological understanding helps to mitigate risks associated with construction in areas prone
to natural disasters, such as earthquakes, floods, or landslides.
Importance of Geology in Civil Engineering
The integration of geological knowledge into civil engineering practices is crucial for the
successful planning, design, and execution of safe, efficient, and environmentally responsible
infrastructure projects (Mishra, 2020). Here are some key reasons why geology is important in civil
engineering:
1.
Provides Information on the Materials Needed for Construction
Geology helps identify the types of rocks, minerals, and soils available in a region.
Engineers need to understand the strength, durability, and suitability of these materials for
construction purposes. For example, limestone and granite are commonly used in building and
road construction due to their strength.
2. Helpful for River Control and Shipping Work
Understanding geological formations helps in the construction of embankments, flood
control structures, and navigation channels. Geologists analyze riverbeds, sediment transport, and
erosion patterns to ensure sustainable river management and prevent flooding or siltation of
shipping routes.
3.
Knowledge is Required for the Foundation of Faults
Faults are fractures in the Earth's crust where movement has occurred. Civil engineers
must assess fault lines before constructing buildings, bridges, or other infrastructure to avoid
areas prone to seismic activity. Geotechnical studies help in designing earthquake-resistant
structures.
4.
Constructing Dams and Tunnels
Dams and tunnels require a thorough understanding of rock formations and groundwater
movement. Engineers must assess the stability of surrounding geological structures to prevent
issues such as landslides, seepage, or structural failure. For example, weak or porous rock
formations may require reinforcement before dam construction.
5.
Economical Design is Advanced
Geological knowledge helps engineers design cost-effective structures by selecting the
best materials and construction methods based on the site’s conditions. Identifying suitable sites
for construction minimizes excavation costs and reduces the risk of failure, leading to budgetfriendly and sustainable projects.
6.
Nature of Soil Materials Can Be Found Out
Geology helps in determining the type and properties of soil, such as clay, sand, silt, or
gravel. Different soils have varying load-bearing capacities, drainage characteristics, and
susceptibility to erosion. Knowing the soil type ensures the proper selection of foundation designs
and construction techniques.
7.
Soil Tests Are Done Before Any Project
Before beginning any construction project, soil tests such as the Standard Penetration Test
(SPT), Atterberg limits test, and permeability tests are conducted. These tests assess factors like
soil strength, compressibility, and moisture content, helping engineers design stable foundations
and avoid settlement or structural failure.
Importance of Engineering Geology in Civil Engineering
Engineering geology is a vital branch of civil engineering that deals with the study of the
Earth's materials, structures, and processes to ensure the safety and stability of construction projects.
It helps engineers understand the subsurface conditions and potential challenges before beginning
any construction. Below is an expansion of its importance:
1. To Be Aware of Possible Challenging Ground Conditions Before Designing and Building
2. It Helps to Identify Areas That Are at Risk of Error
3. To Establish Design Specifications
4. For the Best Possible Choice of Site for Engineering Purposes
5. .In Order to Select the Best Engineering Materials for Construction
Lesson 1.2: Branches of Geology
The field of geology is diverse, encompassing different branches that specialize several
aspects of the Earth. Key branches include:
1. Physical Geology- a study that deals with the Earth’s structure and its physical properties and
composition.
2. Mineralogy- the study of minerals. A mineral is an element or chemical compound that is
normally crystalline and that has been formed as a result of geological processes.
It
discusses the identification of rocks, the production of atomic energy, and the industries
3. Petrology- the study of rocks. A rock is defined as "the aggregation of minerals found in the
earth's crust". It is important in civil engineering, in the process of selecting suitable rocks for
buildings, roads metals, etc.
 Subdivisions of Petrology
a. Metamorphic Petrology- rise from the transformation of existing rock to new types of
rock in a process. Metamorphic rocks make up a large part of the Earth's crust and form
12% of the Earth's land surface.
b. Igneous Petrology- formed from magma. Igneous petrology is closely related to
volcanology, tectonophysics, and petrology in general.
c. Sedimentary Petrology- Encompasses the study of modern sediments such as sand, silt,
and clay, and the processes that result in their formation (erosion and weathering),
transport, deposition, and diagenesis.
4. Structural Geology- a branch of science that deals with the study of structures found in rocks.
Also known as tectonic geology or simply tectonics. It is also an arrangement of rocks and
plays an important role in civil engineering. Examples of structural geology include anticline
and syncline.
5. Mining Geology- It deals with "the study of the application of geology to mining engineering in
such a way that the selection of suitable sites for quarrying and mines can be determined. It is
a combined principle of economic geology and mining engineering to the development of
defined mineral resources. Types of mining methods include underground, open surface,
placer and in-site mining.
6. Photogeology- a branch of science that deals with "the interpretation of aerial photographs".
The main objective of photogeology is to obtain maximum geologic information with minimum
fieldwork.
7. Economic Geology- a branch of Geology that deals with "the study of minerals, rocks, and
materials of economic importance like coal and petroleum. The purpose of the study is to
identify new ore deposits for excavation as well as to understand how ore deposits are
generated and localized within Earth's crust.
8. Geomorphology- the main focus of this branch is to investigate how landforms change over
time and the process in which those landforms are formed.
9. Paleontology- the study of Earth’s history through the analysis of fossils.
Lesson 1.3: Earth Structure and Composition
The Earth can be divided into three layers based on chemical composition, the (a) crust, (b)
mantle, and (c) the core.
CRUST
The crust is the thin outer layer of the earth, and it is the solid rock layer that we live on. The
earth’s crust is either continental or oceanic. The crust averages around 25 miles or 40 kilometers in
thickness and can be divided into 15 major tectonic plates that are rigid in the center and have
geological activity at the boundaries such as earthquakes and volcanoes. The earth’s crust contains
all three rock types including igneous, sedimentary and metamorphic rocks. Oceanic crust is thin
portion that lies under the ocean, and is approximately four miles or seven kilometers in thickness,
with a density of 3.00 grams per cubic meter, and it is composed of dense rocks including basalt.
Continental crust is thicker and ranges from 6 to 47 miles or 1o to 75 kilometers in thickness and with
a density of 2.7 grams per cubic meter.
MANTLE
The mantle is the thickest section of the earth and is located between the crust and the core. It
is a region of hot slow-moving solid rocks. The mantle is 1,800 miles or 2,900 kilometers, and it is
composed of silicate minerals and they’re similar to the ones found in the crust except with more
magnesium and iron. Additionally, heat flows within the earth through convection and conduction. As
the heat rises from the core, it creates convection currents in the semi-solid mantle. The hot mantle
material rises towards the earth’s Crust while the cooler material sinks back down. The convection
current in the mantle create drag on the overlying tectonic plates causing them to move. These plates
can move away from each other (divergent), move towards each other (convergent), or slide past
each other (transform). Moreover, the movement of tectonic plates due to convection currents also
results in geological activities such as earthquakes, volcanic eruptions, and the formation of mountain
ranges.
Compositions of the Mantle
a. Upper Mantle – extends from the crust to about 410 kilometers deep, mostly solid but has
malleable regions that contribute to tectonic activity and is primarily composed of silicate
minerals, including olivine and pyroxene. Within this layer, there are two recognized regions,
the lithosphere and the asthenosphere. The lithosphere is the solid outer part of the earth
including the crust and brittle upper mantle, up to 100 kilometers deep. The asthenosphere,
beneath the lithosphere, is softer and allows for plastic movement over time.
b. Transition zone - A region in the mantle where high-pressure conditions lead to changes in
mineral structures. It lies between 410 and 660 kilometers deep, featuring changes in rocks
due to high pressure and temperature causing them to transform into denser forms.
Minerals like wadsleyite and ringwoodite are found in the transition zones, stable under
extreme conditions.
c. Lower Mantle – the lower mantle extends about 660- 2,900 kilometers deep. Composed of
silicate minerals in a solid state due to high pressures, even though temperatures are
elevated.
d. D’' Layer – it is the lowermost part of the mantle, located just above the outer core. This
layer has unique seismic properties and contains low-shear-velocity provinces and ultra-low
velocity zones.
CORE
The core extends from below the mantle to the center of the earth. Scientists believed that the
core is made mostly of iron and nickel. The core is the densest layer and make about 1/3 of the
Earth’s mass. The outer core is composed mostly of iron and nickel with metals found liquid form. It
reaches a temperature of 7,200 to 9,000 degrees Fahrenheit and it’s estimated to be about 1,400
miles thick or 2,300 kilometers. The inner core is the hottest part of our planet and has a temperature
between 9,000 to 13,000 degrees Fahrenheit. It is a solid layer and is around 755 miles or 1,200
kilometers thick, and it’s composed mostly of iron.
Leson 1.4: Elementary Knowledge on Continental Drift and Plate Tectonics
The Continental Drift Theory
The Continental drift theory was proposed by Alfred Wegner—a German scientist—in 1912.
According to this theory, all continents were joined together in one landmass called Pangaea.
Pangaea is a supercontinent, a huge continent, that is composed of the smaller continents present
today.
245 Million Years Ago
-
Pangaea existed when some of the earliest dinosaurs were roaming the Earth. It was
surrounded by a sea called Panthalassa, meaning “all sea”.
180 Million Years Ago
-
Gradually, Pangaea broke into two big pieces, the northern piece is called Laurasia and the
southern piece is called Gondwana.
65 Million Years Ago
-
By the time the dinosaurs became extinct, Laurasia and Gondwana Split were subdivided into
the continents we know today.
Three Main Evidence Found by Alfred Wegner
1. Geologic or the apparent fit of the continents
Continents look like puzzle pieces. The east coast of South America and the west coast of
Africa seem to fit together like pieces of a jigsaw puzzle. Additionally, Identical rocks, of the same
type and age, are found on both sides of the Atlantic Ocean.
2. Fossils or fossil correlation
Evidence in the places certain fossils is found. Fossils of the ancient reptile Mesosaurus
are only found in southern Africa and South America. Tropical plant fossils from the frigid Arctic
archipelago of Svalbard, Norway.
3. Climate
Evidence in the changing climates during the past. Glacial striations (scratches) and
erratics (rocks moved away by glacial ice from original bedrock) correspond between continents.
Additionally, coral reefs and coal-forming swamps are found in tropical and subtropical
environments.
Seafloor Spreading
The Seafloor spreading Theory states that the oceanic crust forms along the mid-ocean ridge
system and spreads out laterally away from them.( A mid-ocean bridge is a landform that is created
from a divergent boundary, and are found in the ocean floor.) Seafloor spreading is a geological
process in which tectonic plates or large slabs of the earth’s lithosphere split apart from each other.
New ocean floor forms along cracks in the ocean crust as molten material erupts from the mantle
spreading out and pushing older rocks to the sides of the crack. New ocean floor is continually added
by the process of seafloor spreading.
Plate tectonics
The plate tectonics theory states that the uppermost mantle, along with the overlying crust,
behaves as a strong, rigid layer called lithosphere. Due to convection currents, geologists believe that
convection makes tectonic plates move. Moreover, Earth has seven major lithospheric plates that
account for 94% of the Earth ' s surface (North American Plate, South American Plate, Pacific Plate,
African Plate, Eurasian Plate, Indo-Australian Plate, and Antarctic Plate).
Three Main Types of Plate Boundaries
1. Transform Plate Boundary- two plates slide past each other.
2. Convergent Plate Boundary- two plates move towards each other.
3. Divergent Plate Boundary- two plates move away from each other.
Continental Margin
Continental margin refers to the area where continental crust meets oceanic crust. It consists
of three main parts: continental shelf, continental slope, and continental rise.
Parts of Continental Margin
1. Continental Shelf -a flat gently sloping area extending from the coast into the ocean. Shelf
widths can range from 70 to 1,500 kilometers, ending at a depth of about 135 meters. The
shelf break marks the transition where the seafloor drops off sharply.
2. Continental Slope- as steeper decline, with inclinations ranging from 1 to 25 degrees.
Submarine canyons, formed by turbidity currents are common on the continental slope.
3. Continental Rise -Gently-sloping area after the continental slope and before the ocean floor,
accumulating sediments
Trenches -deepest parts of the ocean and these are narrow depressions caused by subduction
zones.
Mid-oceanic Ridge -the mountain range system in the ocean.
Types of Continental Margin
1. Active margins- are associated with tectonic plate boundaries, may lack a continental rise and
feature trenches.
2. Passive margins- passive margins like those along the east cost of the United States are
generally wider and less steep, they lack major tectonic activity and often have thick sediment
layers. Passive margins also consist of continental shelf, continental slope, and continental rise.
References:
Website
Engineering
Geology
for
Civil
Engineers.
(n.d.).
Google
Books.
Retrieve
from
https://books.google.com.ph/books?id=8Ys5brwYEj8C&printsec=frontcover&source=gbs_atb&
redir_esc=y#v=onepage&q&f=false
Libretexts. (2022). 1.3: The Science of Geology. Geosciences LibreTexts. Retrieved from
https://geo.libretexts.org/Bookshelves/Geology/Fundamentals_of_Geology_(Schulte)/01%3A_
Science_of_Geology/1.03%3A_The_Science_of_Geology
Mishra, H. (2020). Importance of Geology in Civil engineering - Civil Wale. Civil Wale. Retrieved from
https://civilwale.com/importance-of-geology-in-civil-engineering/
General
Geology
(group
1)
(PDF).
CliffsNotes.
(n.d.).
Retrieved
from
https://www.cliffsnotes.com/study-notes/4863838
Video
EarthScienceAnswers. (2024). What are the Different layers of the Earth’s [Video]. Youtube.
Retrieved from https://youtu.be/fViXzhppPCM?si=c4A86xesLuQtFGBE
EarthScienceAnswers. (2025). What are the Components of a Continental Margin? [Video]. Youtube.
Retrieved from https://youtu.be/s6dFEwG1LRQ?si=BlevCB1p4Ctrmd47
Elmundo, D.E. (2021). Continental Drift Theory & Seafloor Spreading Theory [Video]. Youtube.
Retrieved from https://youtu.be/tUCFhkBOk_U?si=0WKSrdGE_QKmfq5W
MooMooMath and Science. (2020). Layers of the Earth Based on Chemical Composition and
Physical
Properties
[Video].
https://youtu.be/6RKoLleyDJ4?si=gLqefcLHgfCIO1dj
Youtube.
Retrieved
from